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Ocular dominance, sometimes called eye preference or eyedness, [1] is the tendency to prefer visual input from one eye to the other. [2] It is somewhat analogous to the laterality of right- or left- handedness ; however, the side of the dominant eye and the dominant hand do not always match. [ 3 ]
Eye-trackers measure rotations of the eye in one of several ways, but principally they fall into one of three categories: measurement of the movement of an object (normally, a special contact lens) attached to the eye; optical tracking without direct contact to the eye; measurement of electric potentials using electrodes placed around the eyes.
Slight differences in the length or insertion position or strength of the same muscles in the two eyes can lead to a tendency for one eye to drift to a different position in its orbit from the other, especially when one is tired. This is known as phoria. One way to reveal it is with the cover-uncover test. To do this test, look at a cooperative ...
Listing's law, named after German mathematician Johann Benedict Listing (1808–1882), describes the three-dimensional orientation of the eye and its axes of rotation. Listing's law has been shown to hold when the head is stationary and upright and gaze is directed toward far targets, i.e., when the eyes are either fixating, making saccades, or pursuing moving visual targets.
Heterophoria occurs only during dissociation of the left eye and right eye, when fusion of the eyes is absent. If you cover one eye (e.g., with your hand) you remove the sensory information about the eye's position in the orbit. Without this, there is no stimulus to binocular fusion, and the eye will move to a position of "rest".
Thus, each eye has a slightly different view of the world around. This can be easily seen when alternately closing one eye while looking at a vertical edge. The binocular disparity can be observed from apparent horizontal shift of the vertical edge between both views. At any given moment, the line of sight of the two eyes meet at a point in space.
Classical image of the shape and size of the visual field [28]. The outer boundaries of peripheral vision correspond to the boundaries of the visual field as a whole. For a single eye, the extent of the visual field can be (roughly) defined in terms of four angles, each measured from the fixation point, i.e., the point at which one's gaze is directed.
To observe flash suppression, a small image is first presented to one eye for about a second while a blank field is presented to the other eye. Then a different, small image is abruptly shown, flashed, to the other, second eye at the location corresponding to the image to the first eye. The image to the first eye disappears, even though it is ...